Ethylene Glycol: 3-Step Production

Ethylene Glycol is a widely produced chemical used in many industries from automotive to consumer products. In the automotive industry, ethylene glycol is used as a coolant, and in the consumer products industry, it is used as the main raw ingredient for polyester fibers. The demand for high purity ethylene glycol is projected to increase 50% by 2024 because the demand for the downstream product, polyester fibers, is also increasing. This increase in demand creates an opportunity to meet a projected need. The purpose of this project is to design an ethylene glycol plant capable of producing 99 wt% ethylene glycol while also achieving high cost and energy efficiency. The chosen reaction pathway is the direct hydrolysis of ethylene oxide. This reaction is the most common in the current industry as it is reliable and produces a high yield, around 90% of ethylene oxide is turned to the desired product. Alongside the ethylene glycol, higher-order glycols, di-ethylene, and tri-ethylene, are produced as by-products. These higher-order glycols are used in the textile industry, so profits can be increased, and wastes can be decreased. The design will utilize adaptations of current ethylene glycol process designs with new techniques to optimize energy efficiency without decreasing the profit. One design optimization is using highly energy efficient wiped falling film evaporators instead of the more common flash drums. The plant is designed to produce 450 MMlbs of ethylene glycol per operation year. The location of the plant was chosen to be outside of Houston, Texas near an existing ethylene oxide plant. This location was selected because ethylene oxide is a very unstable compound. Placing the ethylene glycol plant near the ethylene oxide plant enables the raw material to be transported to the plant in a much safer manner.